An acceptable tobacco smoke filter, particularly a cigarette filter, must exhibit a high degree of filtration of tobacco smoke particles, i.e., have high smoke removal efficiency, at an acceptable draw resistance, i.e., pressure drop. The filter must also be capable of economical continuous production. Furthermore, it must be of a firmness sufficient to avoid collapse during smoking and must not unduly distort the taste and odor of the tobacco smoke.
Many materials including cellulose fibers and a variety of synthetic fibers have been suggested for use in tobacco smoke filters. Of these materials, only continuous filament cellulose acetate tow, and to a lesser degree, paper, have met with any degree of commercial acceptance.
There is a continuing search for new tobacco smoke filters meeting the above criteria and having improved smoke removal efficiencies.